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INDIVIDUAL/Meixner: individual-like objects: Example "the round square", but also Example Holmes, fictitious persons and their parts of the body, of which it cannot be said whether they have certain properties or not - "the man who knew that he knew nothing": not Socrates, but INDIVIDUAL (overdetermined: knowledge/ignorance).
INDIVIDUAL/Meixner: set of all properties (instead of individual): Point: if one element is missing, completely different set (identity of sets through identity of the elements) - therefore all properties are necessary -e.g. ((s) determined person at a particular point in time) Example Meixner: "george w.bush": President necessary (not in the case of Bush).
INDIVIDUAL/Meixner: apart from an individual, whose properties are at least partly contingent, there is an INDIVIDUAL assigned to it, which simply consists of the set of the same properties (at that point in time). Since a set loses its identity when an element changes, all properties are necessary here - MeixnerVsLewis: confuses individual with INDIVIDUAL: counterpart needs its properties, because it is individuated by the set (because it is only even singled out by it).
Einführung in die Ontologie Darmstadt 2004